Helical seam follower and welder

ABSTRACT

Apparatus of producing or testing with a welding or testing instrument welded spiral-seamed tubes formed of a steel band, which comprises rolling a steel band in a continuous spiral so as to form a rotating tube-shaped body; placing on the steel band at a constant spacing from an edge of the steel band extending toward a given welding location thereon, a premagnetized tape containing a ferromagnetic material adhering to the steel band and carrying a marking line disposed parallel to the edge of the steel band; sensing the marking line and regulating in accordance therewith the orientation of at least one of the welding and testing instruments with respect to the edge of the steel band so that the instrument and the given welding location are momentarily in registry as the tube-shaped body rotates; and withdrawing the premagnetized tape from the steel band after the steel band edge of the tube-shaped body has rotated past a second one of the instruments in the travel direction of the steel band edge; and apparatus for carrying out the method.

United States Patent Sablotny [54] HELICAL SEAM FOLLOWER AND WELDER [72]Inventor: Adalbert Sablotny, l-lagen-Vorhalle,

Germany [73] Assignee: Hoesch Aktiengesellschaft, Dortmund, Germany [22]Filed: Sept. 16, 1970 [21] Appl. No.: 72,882

Related U.'S. Application Data [62] Division of Ser. No. 769,579, Oct.22, 1968,

Pat. No. 3,557,335.

[30] Foreign Application Priority Data Oct. 27, 1967 Germany ..P 16 52938.1

[52] US. Cl. ..219/62, 29/477.3, 318/18, 324/34 [51] Int. Cl. ..B23k11/02 [58] Field of Search..2l9/76, 62, 59, 60, 124, 125 R, 219/125 PL,126; 324/34, 40; 250/219 RG, 219 S; 29/470, 477.3; 228/8; 318/576, 577,

[4 1 Oct. 3, 1972 3,146,331 8/1964 Schubert ..219/62 3,341,771 9/1967Crouch et al. ..324/38 X 3,118,047 l/l964 Johnson ..219/76 PrimaryExaminerJ. V. Truhe Assistant Examiner-L. A. Schutzman Attorney-Curt M.Avery, Arthur E. Wilford, Herbert L. Lerner and Daniel J. Tick [57]ABSTRACT Apparatus of producing or testing with a welding or testinginstrument welded spiral-seamed tubes formed of a steel band, whichcomprises rolling a steel band in a continuous spiral so as to form arotating tubeshaped body; placing on the steel band at a constantspacing from an edge of the steel band extending toward a given weldinglocation thereon, a premagnetized tape containing a ferromagneticmaterial adhering to the steel band and carrying a marking line disposedparallel to the edge of the steel band; sensing the marking line andregulating in accordance therewith the orientation of at least one ofthe welding and testing instruments with respect to the edge of thesteel band so that the instrument and the given welding location aremomentarily in registry as the tubeshaped body rotates; and withdrawingthe premagnetized tape from the steel band after the steel band edge ofthe tube-shaped body has rotated past a second one of the instruments inthe travel direction of the steel band edge; and apparatus for carryingout the method.

1 Claim, 9 Drawing Figures PATENTEDnm I972 SHEET U 0? 7 Fig, 6

PATENTEDnma I972 SHEET 7 [IF 7 Fly. 9

application Ser. No. 769,579, filed Oct. 22, 1968 now US. Pat. No.3,557,335, issued Jan. 19, 1971 and relates to and apparatus forproducing and/or testing spiral-seamed tubes.

When spiral-seamed tubes are welded, two weld seams or spots arefrequently placed one after the other, for example, a first welding seamis located near the spot at which the edges of the steel band first joinone another, and a second seam or spot is placed at a distance half ofthe pitch from the first welding location.

While it is possible to regulate the welding head lying in the firstwelding seam with the aid of suitable regulating devices so that itmatches variations in the position of the band edge and the width of thewelding gap, difficulties arise in controlling the second welding headbecause the pitch of the applied welding seam, as is known fromexperience, is not constant and, moreover, due to unavoidable sabershape of the band and due to the variations in the slope or pitch of theseam, no constancy exists. Quite similar difficulties arise if a weldingseam applied by means of one or more welding heads is to be tested as toquality on the welding machine by means of an ultrasonic testing headbecause such a head similarly operates without trouble only when it islocated adjacent the welding seam on the base material. Theperpendicular spacing of the ultrasonic testing head with respect to themiddle of the welding seam must be constant within very narrowtolerances.

In order to meet these difficulties, in accordance with German publishedapplication No. 1,214,344, marking line disposed parallel to an edge ofthe band has been applied to the band before welding; it has beenoptically sensed and by a subsequent regulation in accordance therewithat least one welding head and/or at least one testing head has beenoriented with respect to the band edge. The method of my invention makesuse of this feature of the aforementioned German published applicationto produce the marking line.

To produce the marking line, the aforementioned German publishedapplication provides .a simple device in the form of a paint receptaclewith a stirring mechanism and outlet opening, which is secured to asupporting head, that is pressed by a spring-biasing force against thesteel band edge extending toward one of the welding locations andtherewith producesa continuous line directly on the steel band spaced ata constant distance from the steelband edge. This method isdisadvantageous in that maintenance of the color marking is relativelyhigh and the marking line must later'be removedfrom the completed tube.

is accordingly an object of my invention-to provide method and apparatusfor producing and/or testing spiral-seamed tube which avoids theforegoingdisadvantages of the heretofore known methods and apparatus ofthis general type, and more particularly which reduces maintenance ofthe marking and minimizes the time for removing the marking line fromthe'finished tube.

'With the foregoing and other objects in view, I accordingly providemethod for producing and/or testing spiral-seamed tubes formed of asteel band, which comprises rolling a steel band ina continuous spiralso as to form a rotating tube-shaped body; placing on the steel band ata constant spacing from an edge of the steel band extending toward agiven welding location thereon, a premagnetized tape containing aferromagnetic material adhering to the steel band and carrying a markingline disposed parallel to the edge of the steel band; sensing themarking line and regulating in accordance therewith the orientation ofat least one of the welding and testing instruments with respect to theedge of the steel band so that the instrument and the given weldinglocation are momentarily in registry as the tube-shaped body rotates;and withdrawing the premagnetized tape from the steel bad after thesteel band edge of the tube-shaped body has rotated past a second one ofthe instruments in the travel direction of the steel band edge; andapparatus for carrying out the method.

Such a magnetized tape is capable of being applied to the steel band byrelatively simple means very accurately in constant spacing from thesteel band edge and provides therewith a marking line free of alldeviations and inaccuracies, which is suitably sensed so as to regulatewithout any trouble a welding head and/or an ultrasonic testing head.The magnetized tape, which is many times longer than the arc length ofthe welding seam of a single tube, can be used repeatedly.

in accordance with a further feature of the invention, the marking linecan be produced by providing the magnetizedtape with a layer covering apart of the surface thereof and which has a different reflectioncapability than that of the magnetized tape. Also in accordance with theinvention, a layer can be applied to the magnetized tape so as to fullycover the tape, the layer having on the outside thereof a light and adark region separated by the marking line. Naturally, the magnetizedtape may also carry any other marking line, for example a magnetic trackdetectable by a magnetic measuring device.

The apparatus for carrying out the method of my invention includes aguiding head for the incoming magnetized tape, and spring means forforcing the guiding head against one of the steel band edges and forpressing the guiding head against the steel band surface.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin method and apparatus for producing and/or testing spiral seamedtubes, it is nevertheless not intended to be limited to the detailsshown, since various modifications and structural changes may be madetherein without departing from the spirit of the invention and withinthe scope and range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings, in

which:

FIG. 1 is a diagrammatic view partly in perspective of apparatus forcarrying out the method of producing and/or testing spiral-seemed tubesaccording to my invention;

FIG. 2 is a plan view of a portion of the steel band shown in FIG. 1with a portion of magnetized tape adhering thereto FIG. 5 is a sectionalview taken along the line VV in FIG. 4;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 4;

FIG. 7 is a'view corresponding to that of FIG. 6 of another embodimentof the guiding head for the magnetized tape according to my invention;

FIG. 8 is a sectional view taken'along the line VIII- Vlll in FIG. 7;and

FIG. 9 is a schematic view of a suitable optical detecting devicetogether with subsequent regulating system.

Referring now to the drawings and first, particularly, to FIG. 1thereof, there is shown a spiral-seamed tube 1 being formed from a steelband 2 on a tube-winding machine represented only by a pair of rollers 3in the figure. Both steel band edges 4 and 5 are welded together at aspot 6, where they meet for the first time, by arc welding with a firstwelding head 7 represented as a circle. This welding head 7, as shown inthe embodiment of FIG. 1, is located within the tube 1. After the tubehas rotated through an angle of 180, a second welding is effected at thespot 8 by means of a second welding head 9 located outside the tube 1.The weld material of the thus applied double weld seam is inspected atthe spot 10 by means of an ultrasonic testinghead' 11 after the tube 1is rotated further through an angle of 360.

For the foregoing reasons, the second welding head 9 and the ultrasonictesting head 11, as shown in FIG. 9, are axially displaceable so as tobe capable of being adjusted on the previously applied welding seamwithout any difficulty. The location of the welding head 9 and thetesting head 11 is regulated photoelectrically, for example, by means ofa marking line 12 extending adjacent to the weld seam, as is describedmore fully hereinbelow.

The marking line 12 is located on a magnetic tape 13, which is securedto the steel band 2 by magnetic adhesion. By a magnetic or magnetizedtape there is meant herein a flexible tape or band of suitable syntheticmaterial such as cellulose acetate or a polyester known under the tradename Mylar to which a ferromagnetic substance such as iron oxide hasbeen added so that it can be permanently magnetized. The magnetizationis effected in such a way that the tape at least at one of its outersurfaces has the capability of attractingsteel objects or conversely ofadhering magnetically to a steel object. Such magnetic tapes are wellknownto the man of ordinary skill in the art as well as to laymen, andare used for many purposes such as, for example, for the magneticattachment of labels. For the purpose of my invention, a magnetic tapehaving a width of about mm. is adequate.

The magnetic tape 13 is applied in the hereinafter described manner tothe steel band 2 so that the spacing thereof from one edge 4 of thesteel band is constant. The magnetic tape 13 proper is dark in color dueto its own nature. In order to obtain a contrast and an optical markingline 12 therewith, the magnetic tape 13 can be provided, from thebeginning thereof, with a light-colored coating 14, for example intheform of a strip of plastic material, so that the desired marking line12 is produced. Instead of applying a strip, half of the magnetic band13 in the longitudinal direction thereof can be given a light color. Themarking line has a constant spacing d from the steel band edge 4. Aworkable value for the spacing d is about 150 mm.

A guiding head generally identified by the reference I numeral 15 inFIG. 1, serves for applying the magnetic tape 13 to the steel band 2.Two embodiments of this guiding head are shown in enlarged view in FIGS.4 to In the embodiment of FIGS. 4w 6, at one end of a tube traverse orT-shaped coupling 17, two rollers 18 are mounted for free rotation andare maintained in abutment with the steel band edge 4. For this purpose,the tube traverse 17 is secured to one end of an arm 19 which carries atthe other, free end thereof, a piston 20 that is displaceable in acylinder 21. The cylinder 21 contains a helical compression spring 22which tends to displace the arm 19 toward the right-hand side of FIG. 4and thereby ensures the constant engagement of the rollers 18 with thesteel band edge 4. The tube traverse 17 carries at its right-hand end,as shown in FIG. 4, a guide member for the magnetic tape 13, formed ofrelatively wide plates 23 and relatively narrow strips 24 sandwichedtherebetween so as to define a space corresponding to thecross-sectional dimensions of the magnetic tape 13. The guide member 23,24 can be adjusted radially with respect to the axis of the tube 2 bymeans of an elongated hole 25 (FIG. 5) and tensioning nuts 26 (FIG. 6).The middle of the guide member 23, 24 which coincides with the markingline 12 is spaced the aforementioned distance d from the steel band edge4. During the operation, the starting end of the magnetic tape 13 isthreaded through the guide member 23, 24 and brought into engagementwith the outer surface 27 of the steel band 2 so that it adheresthereto. The moment the tube 1 is placed in rotation the magnetic tape13 is entrained therewith due to magnetic adhesion and is maintainedconstantly spaced a distance d from the steel band edge 4 due to theguide member 23, 24. The guiding head for the magnetic tape 13 shownFIGS. 4 to 6 is secured by means of the cylinder 21 to the frame 28 ofthe otherwise non-illustrated tube winding machine.

The structure of the embodiment of the guiding head for the magnetictape 13 according to FIGS. 7 and 8 differs from that of FIGS. 4 to 6 inthat a spring 33 is provided which holds the guiding head in engagementwith the steel band edge 4 and presses it against the steel band 2. Tworollers 18 are again provided which abut the steel band edge 4 and areattached to a shaft 16 that is supported by anti-friction bearingrollers 34a and 34b on the steel band 2. Moreover, the shaft 16 issecured through an arm 30 with a connector member 35 and through a joint31 connected to the free end of the arm 30 to the aforementioned frame28 of the tubewinding machine. The spring 33 exerts a force acting on apoint 32 of the connector member 35 for the arm 30. The spring 33 isshown in phantom in FIG. 8 since it actually lies in front of the planeof the figure. The direction in which the spring tension acts isindicated by the arrow A. The spring 33 simultaneously ensures that theengagement between the antifriction bearing rollers 34a and 34b, on theone hand, and the steel band 2, on the other hand, and between therollers 18, on the one hand, and the steel band edge 4 on the otherhand, is continuously maintained.

The shaft 16 carries between the connector member 35 and theantifriction bearing roller 34b, a holder 29 with a roller 36 freelyrotatably mounted on a pin 38. Below the roller 36 there is providedanother roller 37 corresponding thereto and rotatably mounted on theshaft 16. These rollers 36 and 37 serve for guiding the magnetic tape 13which is coiled around the rollers 36 and 37 in the manner shown in FIG.7.

In operation, the embodiment of FIGS. 7 and 8 does not differ from thatof FIGS. 4 to 6.

The magnetic tape 13 is drawn from a first reel 39 in the manner shownin FIG. 1, is coiled around the tube 1 at least up to spot 10, and isthen withdrawn from the tube 1 by a second reel 40. The magnetic tape 13can therefore be reused after the tube 1 has been completed, requiringthat the coils of the tape 13 wound on the reels 39 and 40 be merelyinterchanged.

To detect or sense the marking line 12, a spot 41 on the line 12 isilluminated by a lamp 42, as shown in FIG. 9. In order to eliminate theinfluence or effect of other light sources, pulsating light is employedby disposing a rotating diaphragm 43 between the lamp 42 and the spot 41to be illuminated. The subsequently connected regulating system is soadjusted that it only responds to light broken at a specific frequencyby the diaphragm 43. The illuminated spot 41 lies partly to theright-hand side and partly to the left-hand side of the marking line 12.Thereby, two illuminated regions of different brightness are formed bythis line 12, as shown in FIG. 9. Both regions are examined by twophotoelectric cells 44 which operate through conventional amplifiers 45and delay lines 46 on a conventional control or regulating mechanism 47,by means of which a geared motor 48 is actuated for axially adjustingeither the welding head 9 or the testing head 11 in one or the otherdirection. Both the lamp 4 with the diaphragm 43 as well as thephotocells 44 follow the displacement of the controlled members, i.e.,the welding head 9 and the testing head 11.

If the marking line 12 travels toward one or the other side, the size ofboth differently bright regions of the light spot 41 vary inversely. Thepreviously matched photocells are thereby differently excited and issuesignals which activate the regulating or control mechanism to displacethe system so far that the photocells return to their original matchedand identical state.'ln this manner, the welding head 9 and the testinghead 11 are always held above the center between both originallyexisting steel band edges 4 and 5 I claim:

1. In apparatus for carrying out a method of producing spiral weldedseamed tubes formed of a steel band comprising means for rolling a steelband in a continuous spiral so as to form a rotating tube-shaped body,means for placing on the steel band, at a constant spacing from an edgeof the steel band and extending toward a given welding location thereon,a premagnetized tape containing a ferromagnetic material adherin to thesteel b nd and carr in a markin line ispoed parallel to die edge of th%seel band; n ieans for sensing the marking line and controlling inaccordance therewith the orientation of a welding instrument withrespect to the edge of the steel band so that the instrument and thegiven welding location are momentarily in registry as the tube-shapedbody rotates, and further controlling in accordance therewith thewelding by the welding instrument; and means for withdrawing thepremagnetized tape from the steel band after the steel band edge of thetube-shaped body has rotated past a given location downstream of thewelding instrument in the travel direction of the steel band edge, theimprovement comprising a guide head for the oncoming premagnetized tape,and spring means for biasing said guide head against the edge of thesteel band and pressing said guide head against the surface of the steelband.

1. In apparatus for carrying out a method of producing spiral weldedseamed tubes formed of a steel band comprising means for rolling a steelband in a continuous spiral so as to form a rotating tube-shaped body,means for placing on the steel band, at a constant spacing from an edgeof the steel band and extending toward a given welding location thereon,a premagnetized tape containing a ferromagnetic material adhering to thesteel band and carrying a marking line disposed parallel to the edge ofthe steel band; means for sensing the marking line and controlling inaccordance therewith the orientation of a welding instrument withrespect to the edge of the steel band so that the instrument and thegiven welding location are momentarily in registry as the tube-shapedbody rotates, and further controlling in accordance therewith thewelding by the welding instrument; and means for withdrawing thepremagnetized tape from the steel band after the steel band edge of thetubeshaped body has rotated past a given location downstream of thewelding instrument in the travel direction of the steel band edge, theimprovement comprising a guide head for the oncoming premagnetized tape,and spring means for biasing said guide head against the edge of thesteel band and pressing said guide head against the surface of the steelband.